patch 8.0.0671: hang when typing CTRL-C in confirm() in timer

Problem:    When a function invoked from a timer calls confirm() and the user
            types CTRL-C then Vim hangs.
Solution:   Reset typebuf_was_filled. (Ozaki Kiichi, closes #1791)

src/getchar.c

@@ -467,6 +467,11 @@ flush_buffers(int flush_typeahead)
 	    ;
 	typebuf.tb_off = MAXMAPLEN;
 	typebuf.tb_len = 0;
+#if defined(FEAT_CLIENTSERVER) || defined(FEAT_EVAL)
+	/* Reset the flag that text received from a client or from feedkeys()
+	 * was inserted in the typeahead buffer. */
+	typebuf_was_filled = FALSE;
+#endif
     }
     else		    /* remove mapped characters at the start only */
     {

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    671,
 /**/
     670,
 /**/